Process for producing stock for leather-board and leather-board.



ALBERT L. CLAPP, F BRAINTREE, MASSACHUSETTS, ASSIGNOR TO HIDE-ITE LEATHER COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

PROCESS FOR PRODUCING STOCK FOR. LEATI-IER-BOARD AND LEATHERFBOARD.

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No Drawing.

7 '0 alt whom it may concern:

Be it known that I, A BERT L. CLAPP, a citizen of the United States, residing at Braintree, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Proc- 1;;esses for Producing Stock for Leather- Board and Leather-Board, of which the following is a specification. A

My present invention pertains to an improved process of producing stock for leather-board, and more specifically for leather-board which is, to a greater or less extent, Waterproof, the board which is produced from the stock being at the same time firm and pliable.

. tent waterproof in itself and rendering the In the broad view or aspect of the invention, it may be said to consist in first forming a filler and thereafter adding such filler to a mass of fibrous leather produced in a beater-engine or the like to give the stock body, the filler being to a greater or less ex board substantially waterproof.

The filler may be formed of various materials, but in order to make a stock which will produce a waterproof yet firm and plimake the board brittle, but on the other hand will, while making it waterproof or substantially so, to a greater or less degree accordingto the filler employed, permit the fibers to retain their elasticity and full length, whereby the fibers will thoroughly mat. Preferably the board will be produced in a; wet machine.

The leather-stock, as heretofore, is beaten up in the beater-engine until it is suficiently disintegrated. While this is being done, the filler may be produced in a separate receptacle. In practice, a tank situated directly over the beater-engine and equipped with a Specification of Letters Patent. I Patented Aug, 311, 191L5 Application filed December 13, 1910. Serial No. 597,071. 7

heater and steam connections is generally employed to prepare the filler.

The first step of the process is to render *the materials from which the filler is produced soluble in water, or to produce an emulsion thereof. This is ordinarily accomplished by employing caustic soda, soda ash, borax, or any other emulsifying agent which will convert the materials of which the filler is formed into a watery solution or emulsion. One combination for this purpose may consist'of, say, rosin 150 parts; glue parts and soda 28 parts, together with from 4:00 to 500 parts of water, After the mass is thoroughly intermixed or emulsified, aluminum sulfate (say 135 parts) is added, which will precipitate the mass and this precipitate forms the filler which is added to the stock in the beater-engine. About 1100 parts of beater-engine stock may be em ployed with the precipitate formed by the above process.

While aluminum sulfate will preferably be employed in the foregoing process, and in the following described modifications, as a precipitating agent, and is preferred as such, still other alum salts or other precipitating agents may be used.

Where glue alone is used in a watery solution and is precipitated by the addition of aluminum sulfate or other suitable precipitant, it is unnecessary, of course, toemploy any reagent to emulsify or dissolve the same. However, it is desirable to use other ingredients with the glue, such as rosin, or other inherently water-repellant substance, as the resultant board is more nearly waterproof than would otherwise be the case. V

Other ingredients may be employed to form the filler as, for instance, casein, which will preferably be used in combination with a fatty oil, which after being emulsified by the agents above specified or their equivalents, will be precipitated by aluminum sulfate or other precipitating agent. In general practice it has been found desirable to' use a combination of fatty oils with some colloid, as glue or casein. Any mineral oil or other water-repellant substance may be added to the mixture,-as it will readily emulsify in the presence of the saponifiable fatty oil.

Another combination which will produce a waterproofing filler may be composed of from 400 to 500 parts of water, red oil 100 parts, red wax 50 parts, casein 100 parts and soda 25' parts, the mixture being afterward treated with aluminum sulfate to the extent of 135 parts, to precipitate the same.

If an excess of aluminum sulfate be added to the mixture from which the filler and waterproofing compound is to be formed, it will harden the precipitated or coagulated mass that is thrown down thereby. This in some instances is desirable, as where a relatively hard board is required.

As soon as the aluminum sulfate has thoroughly acted upon the masscontained in the tank in which the filler is being formed, the precipitate is dumped into a beater-load of leather fibers, thoroughly mixed therewith, and' becomes incorporated with the fibers of the mass. The substance is then ready to be formed into board. It will be seen from the above that the aluminum sulfate acts directly upon the compound in the tank and, therefore, spends itself. By spending itself upon the materials of which the filler is formed, the aluminum sulfate has no effect upon the fibers of the stock in the beater engine and consequently does not tend to harden or render them brittle.

In carrying out this process it is not necessary to neutralize the tannic acid in the leather fibers in the beater-engine at any time during the process. It will be noticed that the amount of aluminum sulfate used when a firm board is desired.

In actual practice it has been found that.

the board produced in this manner, namely, by forming a filler and waterproofing material outside of the beater-engine and thereafter adding such filler to the previously obtained stock, is firm, pliable and waterproof, and the fibers thereof are relatively long and tenacious.

In so far as the generic invention is concerned, I do not desire to limit myself to any of the combinations above specified for producing the waterproofing filler. Soap, glue, casein, any size, or any combination of these ingredients, preferably with the addition of a substance which is inherently water-resisting in its nature, as for instance rosin, fat or fatty oils,.may be employed, so long as they are thoroughly precipitated,

preferably by the use of aluminum sulfate.

No claim is made herein to the specific invention in which the filler is produced from a body of leather, nor to the leather-board as an article of manufacture, which comprises a body of fibrous leather rendered substantially waterproof by the presence throughout the body of a finely-divided, non-fibrous substance produced from leather, such invention forming the subjectmatter of my copending application Serial No. 510,558, filed on or about the 31st day of July, 1909.

2. The process of producing stock for leather-board, which consists in forming a filler comprising a non-alkaline mass precipitated from a colloidal emulsion, and thereafter distributing said mass through a body of fibrous leather pulp.

3. The process 'of producing stock for leather-board, which consists in first forming a filler comprising a non-alkaline mass precipitated from a colloidal emulsion, and thereafter distributing said mass through a body of fibrous leather pulp having an acid reaction.

4. The process of manufacturing stock for leather-board, which consists in distributing a completely formed filler produced as a precipitate from an emulsion of a colloidal substance and an inherently-water-repellant substance, through a mass of fibrous leather pulp.

'5. The process of manufacturing stock for leather-board, which consists in mixing a colloidal substancewith an inherently-water-repellant substance; emulsifying the same with an alkali; producing a precipitate by the addition of a salt of alum; and

finally distributing the completely formed, precipitated filler through a mass of fibrous leather pulp.

6. The process of manufacturing stock for leather-board, which consists in mixing a colloidal substance with an inherently-water-repellant substance in the presence of an emulsifying. agent; precipitating the same by the addition of aluminum sulfate and thereby producing a filler; and thereafter distributing the completely formed filler through a body of fibrous leather pulp.

7. The process of manufacturing stock for leather-board, which consists in mixing a colloidal substance with an inherently-water-repellant substance; emulsifying the same by the addition of caustic soda; adding aluminum sulfate and thereby causing a substantially waterproof precipitate to be thrown down; and finally distributing the precipitate through a body of fibrous leather pulp.

- maaaea S. The process of producing stock for leather-board, which consists in first forming a filler comprising a non-alkaline mass precipitated from an alkaline emulsion of a colloidal substance, and an inherently-water-repellant body; and thereafter distributing said filler through a body of fibrous leather pulp.

9. As a new article of manufacture,

leather-board composed of a body of fibrous leather produced from leather pulp rendered substantially waterproof by the presence throughout the body of a finely-divided substance produced as a precipitate from a colloidal substance.

10. As a new article of manufacture,

leather-board composed of a body of fibrous leather produced from leather pulp rendered substantially waterproof by the presence throughout the body of a finely-divided substance produced as a neutral precipitate from an alkaline emulsion of a colloidal substance, and an inherently-water-repellant substance.

In testimony whereof, I have signed my 25 name to thisspecification in the presence of two subscribing witnesses.

ALBERT L. CLAJPP.

Witnesses:

J. SDNEY STONE, ALEX D. SALISGER. 

